使用laravel更新十进制字段

i have a problem of updating the decimal field in my project this is my view

 <div class="form-group row">
                    <label for="colFormLabelLg" name="rate" class="col-sm-3 col-form-label col-form-label-lg">rate</label>
                    <div class="col-sm-10">
                        <input  value="{{$rate}}" class="form-control form-control-lg" >
                    </div>
                </div>

i'm passing the data from the edit view like this

 public function edit($id)
{$terminal = terminal::find($id);
$rate = $terminal->rate;
return view('terminal.editTerminal',compact('terminal','rate'));}

the update function

public function update(Request $request, $id)
{
    terminal::find($id)->update($request->all());
    return redirect()->route('terminal.index');
}